One of the most common worries about titanium dioxide is that it could be a cancer-causing agent. The link between cancer and titanium dioxide traces back to a 1985 study where rats were exposed to high levels of titanium dioxide for two years, causing lung cancer. However, not all experts are convinced by this study.
Titanium is a metal element found naturally in the environment. When it's exposed to oxygen in the air, it forms titanium oxides that are contained in many minerals, sands, soils, and dusts.
Some small test-tube research has shown that these nanoparticles are absorbed by intestinal cells and may lead to oxidative stress and cancer growth. However, other research has found limited to no effects (13Trusted Source, 14Trusted Source, 15Trusted Source).